The object of the proposed research is to assist in the development of new anticancer drugs by the isolation and structure determination of active antitumor agents from plants. The cytotoxic and/or antileukemic agents of Inga punctata, Guatteriopis sessiliflora, Tabernaemontana johnstonii, T. holstii, and Duranta repens, together with two or three other plants, will be isolated by a combination of systematic fractionation procedures with one or more specific bioassay systems. The isolated compounds will be identified by comparison of their physical and spectroscopic properties with those of known compounds, and the structures of new compounds will be elucidated by modern physical techniques including, in appropriate cases, single-crystal x-ray structure determination. Enough of each active compound will be obtained for preliminary pharmacological testing.